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Hello, 

Since my boost solenoid seems to be acting up (80% leads to wastegate pressure and 85 % to overboost) I'm looking to buy a new one. Can you advice me for a simple, reliable, 1.5 bar max boost solenoid valve that is known to work well with the link ecu's without needing additional relay? If possible I would like a silent one because the old one was making so strong sewing machine sounds that it forced me to set 0 target on low engine speeds just so that I don't have to hear that noise. As far as I know the link ECU output port can handle 0.45 amps which is at the limit of most solenoids I find.Thank you!

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3 hours ago, dynoiasi said:

As far as I know the link ECU output port can handle 0.45 amps which is at the limit of most solenoids I find.Thank you!

The Aux outputs are capable of 2A current.  The most commonly used valve is the MAC 3 port, something like 35a-aca-ddba-oba.  They are widely counterfeited though so make sure you are getting a real one.  

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You are right, only the high side drive is limited to 0.5Amps. I got confused. In the end I ordered an  AEM 30-2400 boost solenoid  which looks similar to a MAC 3 port.For those there was a ridiculous amount of fake/cloned ones. Thank you!

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About 0.5 bar... Anyway, after I replace the boost controller I might reach the conclusion that after all this is all this turbo can make. I seem to be able to make more boost in low rpm's and low gears, but it looks like the turbo cannot sustain the pressure in high gears and high rpm's.

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You turn the knife where it hurts :D The problem with my build is that ridiculously I do not know exactly what turbo I am running :) All I know is that it is a T3/T4 hybrid with 60mm inducer and 50mm outlet size. I received it from someone I trusted (back then) when I started the build and he said it should be good for aroud 300hp. From then a lot of money flew into the build and I put together a pretty decent setup, however the capability of one of the main blocks (the turbocharger) is still not know to me.

Update on my work: I installed the new MAC boost controller and started tweaking it on the street. At 90% PWM it looks like I can build around 0.8bar at 6000RPM which is decent for my goals. I get a HUGE immediate overboost when accelerating around 3500-4000RPM even with 70% Wastegate DC. So I guess the turbo is quite small and flows well up to 4000 but then it looses its momentum.

So on the next tweaking session the plan is to try 100% wastegate DC in the high RPM zone and activate the closed loop boost control in order to keep the overoboost tendency in the low RPM's.  Especially if I step off/on the throttle I get immediate boost cut (set at 1 bar).

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On 5/20/2019 at 4:28 AM, dynoiasi said:

You turn the knife where it hurts :D The problem with my build is that ridiculously I do not know exactly what turbo I am running :) All I know is that it is a T3/T4 hybrid with 60mm inducer and 50mm outlet size. I received it from someone I trusted (back then) when I started the build and he said it should be good for aroud 300hp. From then a lot of money flew into the build and I put together a pretty decent setup, however the capability of one of the main blocks (the turbocharger) is still not know to me.

Update on my work: I installed the new MAC boost controller and started tweaking it on the street. At 90% PWM it looks like I can build around 0.8bar at 6000RPM which is decent for my goals. I get a HUGE immediate overboost when accelerating around 3500-4000RPM even with 70% Wastegate DC. So I guess the turbo is quite small and flows well up to 4000 but then it looses its momentum.

So on the next tweaking session the plan is to try 100% wastegate DC in the high RPM zone and activate the closed loop boost control in order to keep the overoboost tendency in the low RPM's.  Especially if I step off/on the throttle I get immediate boost cut (set at 1 bar).

I dont know what engine or specs are you running cause with that boost you could have 300hp, on some engines even more. If you have to much boost on the midrange you just need to adjust the WGDC map, you dont have to run let say 70-90% of WGDC you could run from 0 to 100 if you need it for your needs. Post a rom and log file to check it out.

 

Regards,

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This is a 2.5l M50 Bmw engine with thinker head gasket. Still struggling with boost control. It seems that with the values which are required to get decent boost response on higher gears, I overboost badly in 1st and second gear. Is this not strange? Isn't it the norm to have bigger boost in the high gears because the engine has more time to build load?

Next thing I'll try is gear dependent wg trim to reduce 1st and 2nd duty cycle around 10%, however doesn't that look strange? Usually you reduce wg DC because of traction problems in low gears, but not because of overboost.

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Ok, I will place here a log file and hopefully you guys have some idea what's happening because I really don't know what to try next. After replacing the boost controller with the MAC 3 port I am back to square 1 and I still can't control the boost. In short what I get is very low boost with 65% WG duty cycle and overboosting with 70%. I disabled closed loop boost control and all the runs are done in top gear on straight road. Otherwise the car runs fine and pulls strong when it is making the right boost. What should be the next step? Measuring the WG pressure with different duty cycles to ensure that it is working properly? Easing off on the internal wastegate spring to allow more control?

 

The log file can be copied from the one drive link below and I also attached the map file.

https://1drv.ms/u/s!Amk_BITNgVuBsSer8-quqXP9Pap8?e=Wmfeco

There are 4 markers in the log: first two show runs at 0% WG duty cycle, third is 65% duty cycle making 33kPa and last marker shows 70% overboosting (actually I lifted off the right foot at 180 kPa because I already overboosted too many times in one day...)

 

Any help is much appreciated, thank you very much!

 

pentrumasina7sep.pclr

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I dont think you are going to be able to get acceptable boost control if 65% gives nothing and 70% is over boost.  What type of wastegate is it?  Can you do a picture of how it is plumbed.  

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It's going to be hard to show a photo of the wastegate because it's a bottom mount turbo with internal wastegate and getting to the wastegate is a royal pain... However on short notice I can attach a photo of the solenoid install. It's a funny hack job which I did because I had no 90 degree pipe connector so I used a 'T' and blocked one output with a piece of wood :)

So it's a classic MAC 3 port valve, port 1 goes to atmosphere (image right side), port 2 which should be the common port according to instructions and my own checks goes to the capsule of the wastegate actuator (left of the image) and port 3 is connected to compressor output (port 3 is going up so I have to use there a 90deg bend.

Today I also double checked the electrical connections and everything seems sound there:

65% WG duty gives 7.6V and 70% duty gives 8.2V, I also measured other values so everything looks fine electrically and I can also hear change in the clicking sounds.

I really have no idea what might be the problem unless the wastegate rod sticks somehow but in this case I guess the response would be not predictable... however the response is predictable but just too sudden. Thanks for the help!

Webp.net-resizeimage.jpg

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It's some sort of filter...From what I saw most of the mac style valves come with such a filter for the atmosphere side. It looks like it's  made of pressed copper wires or something. I just blew through it and it gives noticeable restriction, you think that could be the problem? Aren't these filter supposed to be used in such applications?

filter front.jpg

filter back.jpg

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Confession time: the hose I thought was going to the wastegate was going to compressor and the other way around :( I switched them around and now target boost seems to come around 25 % wastegate and controllable. 

I'm sorry to have wasted your time and to have driven the car in overboost dozens of times while trying to understand what's going on.... unfortunately I was just too sure of how those hoses were connected and I thought of any other complicated explanation but this.

So car pulls strong and it seems that soon the tuning will be done. Next priority is getting the cold start decent but I'll meet you in other topics about that :)

Thank you for your help and good luck!

 

Best regards,

Florin

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